Inquiry into Life Eleventh Edition Sylvia S. Mader Chapter 1 Lecture Outline Prepared by: Wendy Vermillion Columbus State Community College Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

1.1 The Characteristics of Life Living things share the following characteristics in common: High degree of organization Require input of energy and materials Reproduce Respond to stimuli Are homeostatic Undergo growth and development Adapt to their environment

The Characteristics of Life cont’d. Living things exhibit levels of biological organization Cellular level Tissue level Organ level Organ system level Organismal level

Levels of biological organization Fig 1.2

The Characteristics of Life cont’d. Organisms require materials and energy Energy-capacity to do work Photosynthesizers use light to make food Animals ingest food Food molecules yield energy

Living things acquire materials and energy, and they reproduce Fig 1.3

The Characteristics of Life cont’d. Living things reproduce DNA contains hereditary information Genes in DNA molecules allow organisms to reproduce Single-celled organisms reproduce asexually by dividing Daughter cells are genetically identical Multicellular organisms reproduce sexually Each parent contributes one half of genes to offspring Offspring are genetically unique

The Characteristics of Life cont’d. Organisms respond to stimuli by moving toward or away from the stimulus Movement toward the stimulus is called a positive response Movement away from the stimulus is called a negative response Movements are important components of behavior Behaviors are protective and adaptive

The Characteristics of Life cont’d. Living organisms are homeostatic Homeostasis- all processes in an organism that maintain a stable internal environment All organ systems function in homeostasis

The Characteristics of Life cont’d. Living things undergo the processes of growth and development Growth- characterized by an increase in size and cell number Development- all events occurring between conception and death

Living things grow and develop Fig 1.4

The Characteristics of Life cont’d. Living organisms adapt to the environment Adaptations- specific characteristics that increase survival Evolution- process by which species change over time new variations within a species may have a survival benefit Those individuals survive to reproduce

The Characteristics of Life cont’d. Adaptation, cont’d. Evolution can explain both unity and diversity of organisms All organisms share characteristics of life Share common ancestry Diversity results from adaptations to different environments

1.2 Classification of living things Taxonomy- discipline of identifying and classifying organisms Organisms classified into taxons Species-most specific grouping Genus- related species Family- related genera (plural form of genus) Order-related families Class- related orders Kingdom- related kingdoms Domain-the most general grouping of related kingdoms

Classification of humans Table 1.1

Classification of living things cont’d. Domain- most general and largest taxon Based on biochemical evidence Archae-unicellular prokaryotic organisms which live in extremely harsh environments Bacteria-unicellular prokaryotes found in nearly all environments Eukarya- unicellular and multicellular organisms which have DNA contained within a nuclear membrane

Pictorial representation of the three domains of life Fig 1.5

Classification of living things cont’d. Kingdoms Archae and Bacteria- currently under revision Eukarya- divided into the 4 kingdoms Protista- unicellular and multicellular organisms; some photosynthetic, others are heterotrophic Fungi- heterotrophic plant-like organisms Plantae- multicellular photosynthetic green plants Animalia- multicellular heterotrophic animals

Classification of living things cont’d. Binomial nomenclature Each organism is given a scientific name which will be recognized by all scientists Based on Latin Consists of an organism’s genus and species The genus is capitalized and the species is lower-case The entire name is either underlined or printed in italics Example: the scientific name of humans is Homo sapiens

1.3 Organization of the biosphere Biosphere- zone of air, land, and water at Earth’s surface which supports life Population-all members of a species living in an area Community-groups of populations living together Ecosystem-includes communities and the physical environment (soil, air, water) in an area

A grassland, a terrestrial ecosystem Fig 1.6

Organization of the biosphere cont’d. Chemical cycling- chemicals cycle through an ecosystem until they are returned to the environment through death and decomposition Energy cycling-flows from the sun through photosynthesizers to others in food chain and dissipates back to the environment as heat Climate determines location of ecosystems The most diverse ecosystems form where solar energy is greatest

Organization of the biosphere cont’d. Human populations- modify the environment rather than adapt We rely on healthy ecosystems to cycle chemicals through the biosphere, and for many foods and medicines In order for an ecosystem to remain healthy it must remain biologically diverse The impact of human population growth on coral reefs and tropical rainforests has been particularly tremendous Human activities have destroyed 10% of all reefs and have seriously degraded 30% in the past few decades Rainforests are being clear cut for agricultural land

Biodiversity Biodiversity is a reflection of the total number of species, the genetic variability they contain in their genes, and the environments in which they live Present biodiversity of Earth is estimated to be 15 million species (only 2 million currently identified!) Extinction rate- currently about 400 species per day lost Preservation of ecosystems must be of primary importance to ensure our survival and the survival of all living organisms

A coral reef, a marine ecosystem Fig 1.7

1.4 The process of science The scientific method is an orderly process of exploring natural phenomena It consists of a series of steps Identification of a problem through observation Formulation of a hypothesis Experimentation and collection of data Development of a conclusion May lead to a scientific theory

Flow diagram for the scientific method Fig 1.8

Scientific method cont’d Observations- nature is orderly and measurable and natural laws do not change Scientists use all senses for observation, and extend capabilities through instrumentation Hypothesis Use of inductive reasoning to formulate a possible explanation for a natural event Experimentation Deductive reasoning used to determine how to test the hypothesis Experimental design- ensures scientist is testing what he/she wants to test for and that meaningful results will be obtained Control group-goes through all aspects of experiment but lacks factor being tested Experimentation using a model-results are considered hypotheses until tested further on actual subjects

Scientific method cont’d. Data-results of experiment Must be observable and objective Conclusion Formulated from analysis of data May suggest further experiments are necessary Reported in scientific journals so methods are available to other scientists Results must be repeatable For an excellent illustration of the process, refer to pg. 12-13 of your text

Scientific theory Scientists seek to explain the natural world through scientific theories Supported by many experiments and observations Theories are accepted by scientists throughout the world

Science and social responsibility Technology-application of scientific knowledge practical purpose Most technologies have both positive and negative effects responsibility of all people to make decisions about which technologies should be used and which should not decisions may be made at the voting booth Education is imperative